‘Micro,’ by Michael Crichton and Richard Preston

Okay, here’s the deal. You and your pals — grad students, hotshot scientists-to-be — are invited to Hawaii to talk about cutting-edge jobs in microbiology. But after you learn that the company’s owner is a crook and a killer, he uses his new technology to shrink you from six feet tall to half an inch. You escape this fiend by fleeing into an isolated rain forest. You’re safe from the evil scientist there, but you’re soon running for your lives from ants, wasps, owls, centipedes, spiders, bats and other creatures that now seem as big as houses. Or, come to think of it, as big as dinosaurs are to regular-size humans. All of which makes sense because “Micro” is the latest posthumous novel by Michael Crichton, who not so long ago gave us those great people-vs.-dinosaur adventures “Jurassic Park” and “The Lost World.”

Crichton died in 2008 at the age of 66. He studied to be a doctor, but even before he finished medical school, he was writing thrillers. “The Andromeda Strain” made him famous at 27, and his 20-odd books are said to have sold more than 200 million copies in 36 languages. Thirteen of them were made into movies. His novels often combined medical and technological elements with an abundance of adventure and violence. At his death, he left this unfinished manuscript — among others — which was given to Richard Preston, himself a respected author of science-related novels such as “The Hot Zone,” to complete.

Crichton was exceptionally well informed, and his books were often fascinating, but they were written fast and had their ups and downs. In 2006, I reviewed “Next,” the last novel published before his death. It concerned a boy who, because of a genetic experiment gone wrong, had a scientist father and a chimpanzee mother. His father set out to raise him as a normal boy, and with frequent haircuts, a baseball cap and baggy clothes, he passed for a more or less typical kid, although he could climb trees better than most and when aroused would bite your ear off. It was a light entertainment at best.

So what of this sci-fi fantasy about half-inch humans doing battle with mosquitoes and katydids? Well, a reader might grumble, “This is ridiculous,” but he might add, “It’s kinda fun, too.” It’s not so hard to accept the downsizing of the heroes. One way or another, dozens of tales — from “Gulliver’s Travels” to the movie “Fantastic Voyage” — have played with variations in size in search of satire or pure adventure.

The story’s weakness is its heroes. There are seven at the outset, and each could have his job description written on his forehead. Peter is a leader. Karen is a warrior. Erika (she’s German) sleeps around. Danny is a troublemaker. And so forth. There’s a lot of inane bickering among them and a few hints of romance — helped along by nude cavorting under a waterfall — even as they are fighting for their lives. They’re one-dimensional, but they’re human — they’re us — and finally their struggle for survival makes the novel bearable, even gripping at times. Crichton and Preston love the natural world (“They were young scientists and the micro-world revealed a wonderland of unknown life”), but they also know it is bloody in tooth and claw.

"Micro: A Novel" by Michael Crichton and Richard Preston (Harper)

Here’s part of what a soldier ant does to a half-inch man: “A soldier got its mandibles fastened under his chin, and his screams ended with a guttural noise as blood spurted from his throat and drenched the ant’s head.” Here a spider attacks: “Lying on its back, it lifted the man into the air, sinking its fangs deeper . . . pumping venom into him.” In these awful yet dispassionate scenes, and there are many of them, the authors adopt a bracing realism. They let admirable characters perish along with the nasty ones; in this Darwinian world, there’s no good or bad; we’re all just protein.

The authors go over the top sometimes, as when one character is swallowed by a bird, and soon after that another is carried off by a wasp. Heroic but improbable rescues ensue. When, halfway along, we’re told there are tiny airplanes hidden in the forest, we know there will be a tiny dogfight — micro-planes versus bats, actually — before the tale is done. On a more realistic note, Crichton has his villain promising to supply our government with lethal micro-drones that could kill any leader on Earth; there’s little reason to doubt such weapons are on the drawing board.

All in all, let’s call “Micro” a mixed bag — sometimes silly, sometimes scary — that will probably find millions of readers. Insofar as it will encourage them to reflect on the mingled beauty and horror of this world, that’s all to the good.